1. Technical Field
The present invention relates to an electrostatic latent image developing toner.
2. Description of Related Arts
In recent years, electrophotographic type image forming apparatuses have faced demands for further enhancements in speed, image quality, and the range of applications. Also for the electrostatic latent image developing toners (hereinafter, may be simply referred to as “toners”) that are used for those image forming apparatuses, development of toners that can cope with the demands of the market is in rapid progress. For example, with regard to a toner for coping with image quality enhancement, it is requested that the toner have a sharp particle size distribution. When the toner has a uniform particle size, and thus the particle size distribution becomes sharp, the individual toner particles have uniform developing behavior, and the reproducibility of microdots is markedly improved. However, in conventional production methods for toner according to a pulverization method, it has not been easy to obtain a sharp particle size distribution of a toner. In this regard, an emulsion aggregation method has been suggested as a production method capable of arbitrarily controlling the shape of toner particles or the particle size distribution. This method is to obtain toner particles by mixing an emulsion dispersion liquid of resin particles with a colorant particle dispersion liquid, or optionally with a mold release agent dispersion liquid; aggregating individual particles, while stirring the particles, through the addition of an aggregating agent or the control of pH; and fusing the particles through heating.
Furthermore, from the viewpoint of preventive measures for global environmental warming, there is an increasing demand for energy savings even for electrophotographic type image forming apparatuses, and thus, development of low-temperature fixing toners that can be fixed with less energy is in progress. A representative study for lowering the fixing temperature of a toner involves the use of a crystalline material.
For example, in order to achieve sufficient low-temperature fixability, for a toner containing a crystalline polyester resin and an amorphous resin, it has been suggested to promote sharp melting by incorporating the crystalline polyester resin that constitutes the toner matrix particles as a polyester resin having a thread-like crystal structure, and regulating the domain size of the crystalline resin (see, for example, Japanese Patent Application Laid-Open No. 2013-257415). Furthermore, in order to achieve excellent folding endurance and heat storage performance even in a case where a crystalline resin is used, a toner having a structural body in which a crystalline polyester resin and a mold release agent are brought into contact, has been suggested (see, for example, Japanese Patent Application Laid-Open No. 2008-33057).